1. Field of the Invention
The present invention relates to a composition for a polishing pad and a polishing pad using the same, and this polishing pad can be suitably utilized for polishing the surface of semiconductor wafer and the like.
2. Description of the Related Art
As a method for polishing which can form the surface having the high flatness, an attention has been recently paid to CMP (Chemical Mechanical Polishing). In CMP, polishing is performed by flowing down a slurry which is an aqueous dispersion in which abrasives are dispersed to the surface of a polishing pad from an upper side while sliding a polishing pad and a side to be polished.
A factor which has a great influence on the productivity in this CMP is the removal rate and, this removal rate is expected to be improved remarkably by setting at a greater amount of the retained slurry than previously used amount.
Hitherto, in CMP, a polyurethane foam containing fine air bubbles has been used as a polishing pad, and polishing has been performed by retaining a pore opened on the surface of this resin (hereinafter, referred to as “pore”).
However, in the polyurethane foam, it is difficult to control the foaming freely, and it is extremely difficult to control a size of foamed air bubbles, a foam density, and the like through the foam uniformly. As a result, the quality of a polishing pad comprising a polyurethane foam varies, leading to the cause for the varied removal rate and the procession state.
As a polishing pad in which controlling of a pore is easier upon this foaming, there are known soluble materials dispersed in a number of resins described in Japanese Patent laid-open publication Hei 8-500622, Japanese Patent laid-open publication 2000-34416 and Japanese Patent laid-open Publication 2000-33552, and the like. Among them, the effectiveness of a polishing pad containing solubles materials is suggested in Japanese Patent laid-open publication Hei 8-500622 and Japanese Patent laid-open publication 2000-33552. However, a matrix material is not studied when it is actually used as a polishing pad.
In addition, a component material is studied in Japanese Patent laid-open publication 2000-34416 and the more stable polishing and an improvement in the removal rate are recognized but a further improvement in the slurry retaining properties and the polishing rate is required.